My research for my answer to Which alphabet were the original Torah scrolls in? gave me an idea--Since the Early Alphabetic alphabet is also called Sinaitic, and the timing seems about right, maybe the Alphabet was also given at Sinai along with the Tablets and Laws...quite a gift to us and the world! Is there any information in the extant literature on this possibility?

There is a braisa quoted in Megillah and Shabbos that R'Chisda says the mem and samech of the luchos stood via a miracle. I understand that to mean that they were composed of an outer shape (oblong or circular) and an inner portion which miraculously did not fall out. That's one clue.
– Avrohom YitzchokOct 15 '12 at 21:52

Would you please edit the basis for your belief into your answer? No offense, but your belief alone is not worth much for those of us who don't know you (which is most of us).
– msh210♦Oct 17 '12 at 6:52

@OptionParty, this would be an interesting answer if you have references for it. Thank you for helping others to shinan'tam as well
– ZachariahOct 17 '12 at 13:59

...that ieue.org site looks like they have the answers to EVERYTHING, and they must, because they KNOW they're right--LOL! So far, the earliest Early Alphabetic/ProtoSinaitic in those pages is from the Sinai mines--some say 15th/14th century BCE, others say 19th...so nobody's SURE. Our ancestors were in the Sinai, the literate ones were familiar with the Heiroglyphic signs, G-d possibly gave them the alphabet to use-the more I think about it, the more it makes sense...our ancestors wandering the Sinai had plenty of time to teach it to other populations there and in Canaan as they travelled...
– GaryOct 19 '12 at 2:24